Magnetically controlled commutator devices



April 23, 1963 M. s. SHEBANOW 3,087,030

MAGNETICALLY CONTROLLED COMMUTATOR DEVICES Filed June 3, 1960 2 Sheets-Sheet 1 INVENTOR. [Malawi 5'. Sheba 220w v MWM M HTTORIVEK A ril 23, 1963 M. s. SHEBANOW 3,087,030

MAGNETICALLY CONTROLLED COMMUTATOR DEVICES Filed June 3, 1960 2 Sheets-Sheet 2 i IIIIIIII/4 INVENTOR. a mime] S. Sheba w BY MWM W it Stats 3,087,630 MAGNETIQZALLY CONTROLLED CQMMEUTATGR DEVICES Michael S. Shebanow, Pelham Manor, NH assignor to Sperry Rand (Iorporation, New York, N.Y., a corporation of Delaware Filed June 3, 1969, Ser. No. 33,746 17 Ciaims. (Cl. Mill-87) This invention relates generally to devices for opening and closing electrical circuits and, more particularly, to devices of this class commonly referred to as commutators wherein one or more circuits are controlled in timed relation to a mechanically moving member.

In commutator devices of the sort above mentioned, especially those designed for operation at high speed, a major problem has been the malfunctioning of the contact elements of the respective circuit switching means after a period of time. Said malfunctioning may take the form of an irregularity or increase in contact resistance or in switch operating time which frequently results from wear or corrosion of the contact elements. It has been found that the life expectancy and operating characteristics of contact elements can be greatly improved by mounting the contact elements in a sealed enclosure. A switching device having contacts so arranged is disclosed in United States patent to W. B. Elwood No. 2,289,830, issued July 14, 1942. In the switching device disclosed in said patent, the contact elements are formed of a magnetizable material so as to serve also as armatures when under the influence of a magnetic field from a magnetic source external to the sealed enclosure. Switches of this type are also known as reed switches and will be so referred to hereinafter in the specification.

The present invention represents a practical application of the use of reed switches to a high speed commutator device. In accordance with the invention there is provided at least one of said reed switches mounted in a fixed position, a permanent magnet mounted to provide lines of magnetic force parallel to the contact elements, and a driven member for periodically subjecting said contact elements to the influence of said magnet. In one embodiment of the device, the permanent magnet is mounted on the driven member so as to periodically move into proximity to the contact elements. In another embodiment of the invention the permanent magnet is fixedly mounted in proximity to the contact elements of the switch, and the driven member comprises a magnetically soft element periodically traversing the area between the magnet and the switch, which element acts periodically to shield the switch from the magnet by providing for the magnet a path of low reluctance in parallel with the switch gap.

Although reed switches, as above mentioned, have operating characteristic which remain constant over long periods of time thereby contributing to the reliability and long life of this form of switch, it has been found that it is not possible to manufacture this type of switch with absolute uniformity, especially regarding switch operating time, or sensitivity, with the result that if two switches were to be simultaneously subjected to magnetic fields of the same strength, a slight variation would likely result between the time one switch operates and the time of operation of the other. In certain high speed applications, the requirements of the associated circuitry might be so critical as to be unable to tolerate the variation in sensitivity from one switch to another without means being provided to compensate for such variations. Accordingly, it is a feature of the instant invention to provide means for adjusting the sensitivity of the switch thus avoiding the necessity of requiring an extremely fine physical adjustment in the mounting of the switch element itself relative to its associated magnet. The adjustable feature of the instant invention comprises a magnetically soft member mounted adjacent to the switch enclosure and adjustably positionable along said enclosure to a setting at a selected distance from the gap between the contact elements. The adjustable member represents a variable reluctance path in parallel with the switch gap path of reluctance. Since the magnetomotive force is constant, the flux available to operate the switch changes as a function of the relative position of the adjustable element along the axis of the switch enclosure.

It is, therefore, an object of the invention to increase the durability, reliability and operating characteristics of commutator devices of the sort described.

It is a further object of the invention to enable construction of a commutator device employing ensealed contacts as the switching element of the device.

It is a further object of the invention to enable a simple and accurate adjustment of the sensitivity of the magnetically controlled contact elements of a switching device.

Further objects of the invention, together with the features contributing thereto and advantages accruing therefrom, will be apparent from the following description when read in conjunction with the drawings wherein:

FIG. 1 is a view of one embodiment of the invention wherein the permanent magnet is mounted on a mechani cally driven member.

FIG. 2 is a sectional view taken along the lines 2-2 of FIG. 1.

FIG. 3 is a sectional view of another embodiment of the invention adapted for control of a single circuit wherein the permanent magnet and the switch are in fixed relation to each other and the driven member comprises a disc disposed between the magnet and the switch.

FIG. 4 is a sectional view taken along the lines 4-4 of FIG. 3.

FIG. 5 is a sectional view of another embodiment of the invention similar to that of FIG. 2 except for being adapted for control of a plurality of circuits.

FIG. 6 is a view of still another embodiment of the invention wherein the permanent magnet and switch are disposed in fixed relation to each other, and the driven member is in the form of a drum having its peripherial surface disposed between the magnet and the switch.

FIG. 7 is a sectional view taken along the lines 7-7 of FIG. 6.

FIG. 8 is a sectional view of still another embodiment of the invention similar to that of FIG. 6 except for being adapted for control of a plurality of circuits.

FIG. 9 is a detail sectional view in large scale of the magnetically control switch element of thedevice together with a sensitivity adjusting member mounted thereon.

Referring first to FIG. 9, there is shown a magnetically controlled reed switch of a type which may be employed with each of the embodiments of the instant invention. The switch comprises a pair of contacts 11, 12 supported in an air tight vessel or envelope 13 which preferably is of a substantially tubular shape and is formed of glass or any other like material having non-conducting and non-magnetic characteristics. The contacts 11, 12 are made of a magnetizable material, such as iron or the like, and are supported on opposite ends of the vessel 13, the contacts extending through the vessel thereby providing exterior terminals by which the switch may be connected by any suitable means in an electrical circuit. The contacts are supported so that their inner extremities normally overlap in spaced apart relation to provide a contact gap and are sufliciently resilient so as to be drawn together closing said gap when the switch is subjected to a magnetic field as hereinafter more fully described.

In FIG. 9 is also shown a sensitivity adjustment memher which comprises a ring or collar 14 which is made of a magnetically soft material and which is adjustably positionable along the axis of envelope 13. A set screw 15, threaded through the ring so as to bear on the envelope 13, serves to lock the ring in an adjusted position. The ring or collar 13 of magnetically soft material, which may also be in other structual forms such as a clamp, spring clip or the like, constitutes, in relation to the magnetic circuit provided by contacts 11, 12 a low reluctance path which in the position shown is parallel to the path of reluctance provided by the switch contact 12. As hereinafter more fully described, the external magnetizing source for operating the switch is so disposed as to create lines of force extending substantially parallel to the switch contacts 11, 12 and across the contact gap thus magnetizing the contacts in opposed polarity causing the switch to operate. Thus, it will be apparent that by adjusting the ring 14 along the axis of the envelope 13 to various gap positions relative to the contact 11, varying amounts of the magnetic field will be diverted from the gap between contacts 11, 12 by the parallel path of reluctance so established. The closer the ring 14 is to the contact 11 of the switch, the more effective it will be in diverting a portion of the magnetic field from bridging the contact gap. Accordingly, since the magnetic field developed for operating the switch varies from zero to maximum density during a specific time internal as a function of a mechanically moving member of the device, the sensitivity or timing of the operation of the contacts during the build up and collapse of the magnetic field about the switch may be varied simply by adjusting the position of the ring 14 along the axis of the envelope 13.

FIGS. 1 and 2 illustrate one embodiment of the device designed for applications wherein it is desired to control a plurality of circuits during one operating cycle. This embodment might be used as a commutator for high speed business machines controlled by punched record cards wherein the record sensing means of the machine requires separate circuits to be completed in timed relation to the passing of each record index position past the sensing device. One form of record card now in use contains index positions in columns of six each thus requiring six separate circuits to be completed as the record passes the sensing device. The device of FIGS. 1 and 2 is designed for accomplishing such a function, it being provided with six separate reed switches 10 which are mounted at suitably spaced positions about the periphery of a supporting drum 21. The supporting drum 21 may be made of any suitable non-magnetizable material possessing sufi'icient rigidity to maintain the switches in an arcuately aligned relationship as shown. The surface of the supporting drum may preferably be cut away to form elongate slots 22 into which the envelope 13 of each switch is seated. The switches are secured to the drum by spring clips 23 which may be fastened by any suitable means, such as rivets, to the surface of the drum adjacent the slots 22 and which are designed to receive the terminal ends of the contacts 11, 12 of each switch. The clips 23 may be made with a tab portion which, since the clips are formed from a good conducting material, provide a terminal by which each switch may be connected in an electrical circuit. The drum is mounted by any suitable means (not shown herein) in concentric relation to a shaft 25 to which is clamped a magnet supporting arm 26 of non-magnetizable material one end of which is split and provided with a clamping screw 27 by which the arm may be adjustably fixed to the shaft 25. The other end of the arm 26 carries a permanent magnet 28 having its poles aligned parallel to the axis of shaft 25, which magnet is secured to the end of the arm 26 by any suitable means such as a screw 29. The arm 26 is mounted in such a position along the shaft 25 as to center the permanent magnet 28 with respect to each of the reed switches 10 so that the magnetic field of the magnet as it sweeps past each of the switches will embrace the contact ends of both contacts 11, 12 of each switch.

With this device utilized as a commutator for a punched card business machine, the shaft 25 would be driven in synchronism with the record card feeding means so that as each card passes the sensing means of the machine a plurality of switches will be operated in succession in precisely timed relation to the feeding of a card. As the shaft 25 makes one complete revolution, each switch in turn is subjected to the field of the permanent magnet 28, the relative timing of the operation of the switch being dependent upon its relative location about the periphery of the supporting drum 21.

It will be noted that since the supporting drum 21 is concentric shaft 25, and since only one permanent magnet 28 is employed, each of the switches will be subjected to a magnetic field of the same density. Accordingly, if the operating characteristics or sensitivity could be made exactly identical, a precise timing in operation of the circuits would result from precise location of the switches about the periphery of the supporting drum 21. However, since the operating characteristics of the switches are not precisely identical, the sensitivity adjusting rings 14 may be employed in applications where the controlled circuitry is unable to tolerate minor variation in sensitivity between one switch and another. Accordingly, whenever a switch is found to be over sensitive in relation to the other switches, the adjusting ring 14 is moved to a position closer to the gap between the switch contacts so as to reduce switch sensitivity. Likewise, if a switch is found to be under sensitive in relation to other switches, the adjusting ring 14 may be positioned further away from the contact gap so as to thereby increase the sensitivity of the switch. This adjusting feature eliminates the necessity for providing a more complex and adjustable mounting means for the switch envelopes 13 and thus makes it feasible and practical to utilize switches of the type herein disclosed in commutators operating at high speeds in circuits requiring highly critical timing.

FIGS. 3 and 4 illustrate another embodiment of the invention which is designed for application wherein it is desired to interrupt a single circuit a plural number of times during one complete revolution of the commutator device. In this embodiment of the invention, a reed switch 30, similar to the switch It hitherfore described, and comprising contacts 31, 32 in an air tight envelope 33 is supported in spring clips 34 carried by a bracket member 35 which in turn is fastened to an outer casing 36. Also supported from the casing by a bracket 37 is a permanent magnet 38 which in this instance is stationary and mounted in fixed relation to the reed switch 30. Magnet 38 is mounted centrally of switch 30 with its poles in position to create lines of force paralleling the switch contacts 31, 32 and extending over the contact gap area of the switch. Disposed between the magnet 33 and switch 39 is a disc 41 made of magnetically soft material and formed with slotted openings 4-2 arranged at spaced intervals about the disc, each extending in a radial direction. The disc is mounted on a shaft 43 which may be driven by any suitable means so as to operate the commutator in synchronism with the device to be controlled thereby. The unslotted area of the disc 41, when interposed between magnet 38 and switch 30 serves to provide a low reluctance path for the magnetic field of the magnet thereby effectively shielding the switch 30 from the field of the magnet. Accordingly, as the disc rotates to bring a slotted opening 4-2 of the disc in line with the magnet 38 and switch 31 the switch will be subjected to the magnetic field causing the contacts to close until the slotted opening moves out of line whereupon the magnetic field is then again diverted away from the switch causing the switch to open and so on as the disc revolves alternately shielding and exposing the switch to the field of the magnet as the disc completes one full revolution. If desired, the sensitivity adjusting member of the type here- '5 tofore described may be utilized with this embodiment of the invention. However, since this embodiment of the invention, shown in FIGS. 3 and 4, utilizes only one reed switch 30, sensitivity adjustment does not present the same problems as in the embodiment in FIGS. 1 and 2.

FIG. discloses an embodiment of the invention similar to that of FIGS. 3 and 4 except for being adapted to control a plurality of circuits during the course of one revolution of the device. In the embodiment of FIG. 5, the outer casing 36 supports a plurality of reed switches 30a30f at suitably spaced positions within a common plane. It also supports a separate permanent magnet 38a-f in position for operating each of the respective switches 30a30f. In this embodiment the disc 41 of magnetically soft material, disposed between the permanent magnets and their respective switches, is provided with a single slotted opening 42 so that as the shaft 43 drives the disc 41 causing the slotted opening to pass each of the switches and their respective magnets in turn, each of the switches will be momentarily operated in succession at a predetermined time in an operating cycle of the device. Since this embodiment of the invention utilizes a plurality of reed switches, the sensitivity adjusting feature heretofore described may be advantageously employed in applications where an extremely fine timing of the operation of the switches is required.

FIGS. 6 and 7 illustrate a still further embodiment of the invention designed for interrupting a single circuit and similar to the embodiment of FIGS. 3 and 4 except for the structural form of the magnetically soft driven member disposed between the reed switch and its associated permanent magnet. In the embodiment of 'FIGS. 6 and 7, a reed switch 50, similar to switches 30 and heretofore described, and comprising contacts 51, 52 enclosed in an air tight envelope 53, is supported by clips '54 fastened to a bracket 55 of insulating material which in turn is supported by an arm 56. Also supported by the arm 56 is a bracket 57 to which is fastened a permanent magnet 58 mounted in proximity to the switch and in position to operate the same. In this embodiment of the invention, the driving shaft 59 carries a magnetically soft member 60 in the structural form of a drum, the peripheral surface of which is disposed to lie in the area between the switch 50 and its associated permanent magnet 53. The peripheral surface of the drum is formed a plurality of slotted openings 61 arranged in predetermined spaced positions around its circumference, each of the openings extending in an axial direction so as to expose the switch to the magnetic field of the permanent magnet as the slot comes into alignment therewith. Accordingly, as the drum 6t) driven by shaft 59 completes a revolution causing the slotted openings 61 to sweep between the switch 50 and its permanent magnet 58, the switch will be momentarily operated through a succession of predetermined periods during each operating cycle of the device.

In FIG. 8 a modified version of FIGS. 6, 7 embodiment is shown in a design adapted for controlling a lurality of circuits during an operating cycle of the device. In the embodiment of FIG. 8, a plurality of reed switches 50af each with its own separate magnet 5851- in fixed relation thereto, are mounted at predetermined locations around a supporting plate 62. In this embodiment, the peripheral surface of the drum 6t? driven by shaft 59 is provided with a single slotted opening 61 so as to operate the switches 58a-f in succession at predetermined periods of an operating cycle as the drum completes one revolution. With this embodiment of the device, the sensitivity adjusting feature heretofore described may also be advantageously employed, in the event that the controlled equipment requires extremely critical timing which could not tolerate possible variations of sensitivity between the respective switches.

From the foregoing it will be apparent that the invention, in all of the embodiments herein shown and described, represents a feasible and practical application of the use of magnetically controlled reed switches in a circuit interrupting or commutator device, thereby providing a device of the character described in a simplified design economical to manufacture and capable of operating reliably at high operating speeds over a relatively long life span.

While there has been shown and described what are regarded as preferred embodiments of the invention, it is obvious that changes in form could be made without departing from the spirit of the invention, and it is intended therefore that the invention be not limited to the exact forms shown and described nor to anything less than the whole of the invention as hereinbefore set forth and hereinafter claimed.

What is claimed as new and desired to be secured by Letters Patent is:

1. A commutator device of the character described comprising electrical switching means including a pair of elongate resilient contacts mounted in parallel relation to each other with the contact surfaces thereof spaced apart to form a contact gap, said switching means defining a path of reluctance and being operable under the influence of a magnetic field to close said contact gap, permanently magnetized means having its magnetic axis disposed substantially in alignment with said path of reluctance to provide a magnetic field directly embracing said switching means and extending in a direction to operate said switching means, a magnetizable member of curvilinear shape disposed around said switching means and adjustably mounted in relation to the contacts of said switching means to provide in the field of said permanently magnetized means a path of variable reluctance parallel to the reluctance path defined by the contact-S of said switching means, and a cyclically rotatable member for periodically subjecting said switching means to the magnetic field of said permanently magnetized means.

2. The invention according to claim 1 wherein said pair of contacts are contained within an air tight enclosure formed of non-magnetic material.

3. The invention according to claim 2 wherein said contacts are formed of a magnetizable material and constitute the path of reluctance defined by said switching means.

4. The invention according to claim 1 wherein said switching means includes a plurality of switch devices each including a pair of said resilient contacts, said devices being mounted at predetermined spaced positions within an arc concentric to the axis of said rotatable member, whereby said devices are successively operated in turn at predetermined intervals during a complete cycle of said rotatable member.

5. The invention according to claim 4 wherein said cyclically driven member comprises an arm fastened to a rotating shaft and said permanently magnetized means is carried by said arm in a path lying adjacent each said switch device.

6. A commutator device of the character described comprising electrical switching means including a pair of elongate resilient contacts mounted in parallel relation to each other with contact surfaces thereof spaced apart to form a contact gap, said switching means defining a path of reluctance and operable under the influence of a magnetic field to close said contact gap, permanently magnetized means mounted in fixed relation to said switching means and having its magnetic axis disposed substantially in alignment with said path of reluctance to provide a magnetic field embracing said switching means and extending in a direction to operate said switching means, a magnetizable member of curvilinear shape disposed around said switching means and adjustably mounted relative thereto for providing in the field of said permanently magnetized means a variable reluctance path parallel to the reluctance path defined by said switch ing means and a cyclically driven rotatable member of magnetizable material disposed and constituting a magnetic shield between said switching means and said permanently magnetized means and formed with at least one opening adapted to align with said switching means and said permanently magnetized means for periodically subjecting said switching means to the magnetic field of said permanently magnetized means.

7. The invention according to claim 6 wherein said pair of contacts are contained within an air tight enclosure formed of non-magnetic material.

8. The invention according to claim 6 wherein said contacts are formed of a magnetizable material and constitute the path of reluctance defined by said switching means.

9. The invention according to claim 6 wherein said cyclically driven member is in the form of a disc and rotates about an axis perpendicular to the magnetic axis of said permanently magnetized means.

10. The invention according to claim 6 wherein said cyclically driven member is in the form of a disc having a single one of said openings and rotatable about an axis perpendicular to the magnetic axis of said permanently magnetized means and wherein said switching means includes a plurality of switch devices each including a pair of said resilient contacts, said devices being mounted at predetermined spaced positions within an arc concentric to the axis of said rotatable member.

11. The invention according to claim 6- wherein said cyclically driven member is in the form of a disc having a plurality of said openings and rotating about an axis perpendicular to the magnetic axis of said permanently magnetized means.

12. The invention according to claim 6 wherein said cyclically driven member is in the form of a drum rotatable about an axis parallel to the magnetic axis of said permanently magnetized means.

13. A commutator device of the character described comprising electrical switching means including a pair of elongate resilient contacts mounted in parallel relation to each other with contact surfaces thereof spaced apart to form a contact gap, said switching means defining a path of reluctance and being operable under the influence of a magnetic field to close said contact gap, permanently magnetized means mounted in fixed relation to said switching means and having its magnetic axis disposed substantially in alignment with said path of reluctance to provide a magnetic field embracing such switching means and extending in a direction to operate such switching means, and a cyclically driven drum of magnetizable material rotatable about an axis parallel to the magnetic axis of said permanently magnetized means, the peripheral portion of said drum being disposed between said switching means and said permanently magnetized means and containing at least one opening adapted to align with said switching means and said permanently magnetized means for periodically subjecting said switching means to the magnetic field of said permanently magnetized means.

14. The invention according to claim 13 wherein said switching means includes a plurality of switching devices each including a pair of said resilient contacts said devices being mounted at predetermined spaced positions within an arc concentric with the rotatable axis of said drum, the peripheral portion of said drum containing a single said opening, whereby said switch devices are successively operated in turn at predetermined intervals during the rotation of said drum.

15. A sensitivity adjusting device for magnetically controlled switching means having a pair of elongate resilient contacts mounted in parallel relation to each other with contact surfaces thereof spaced apart to form a contact gap, said contacts defining a path of reluctance and operable under the influence of a magnetic field to close said contact gap, said device comprising, a curvilinear magnetizable member disposed around one of said contacts so as to lie between said one contact and the source of said magnetic field and adjustably positionable longitudinally of said one contact to provide with the other said contact a path of reluctance parallel to the reluctance path defined by said one contact and said contact gap.

16. The invention according to claim 15 wherein said magnetizable member is in the form of a collar extending around said one contact.

17. The invention according to claim 15 wherein said pair of contacts are contained within an air tight enclosure tormed of non-magnetic material and said magnetizable member is adjustably mounted on said enclosure.

References Cited in the file of this patent UNITED STATES PATENTS 593,230 Moore Nov. 9, 1897 2,180,701 Wilson Nov. 21, 1939 2,187,369 Uehling Jan. 16, 1940 2,332,338 Peek Oct. 19, 1943 2,872,597 Ormond Feb. 3, 1959 2,922,994 Kennedy Jan. 26, 1960 2,932,699 Reese Apr. 12, 1960 2,945,931 Reese July 19, 1960 2,983,792 Nitsch May 9, 1961 2,999,914 Stanaway Sept. 12, 1961 3,013,137 Vauden Broeck Dec. 12, 1961 FOREIGN PATENTS 538,409 Great Britain Aug. 1, 1941 1,068,813 Germany Nov. 12, 1959 

1. A COMMUTATOR DEVICE OF THE CHARACTER DESCRIBED COMPRISING ELECTRICAL SWITCHING MEANS INCLUDING A PAIR OF ELONGATE RESILIENT CONTACTS MOUNTED IN PARALLEL RELATION TO EACH OTHER WITH THE CONTACT SURFACES THEREOF SPACED APART TO FORM A CONTACT GAP, SAID SWITCHING MEANS DEFINING A PATH OF RELUCTANCE AND BEING OPERABLE UNDER THE INFLUENCE OF A MAGNETIC FIELD TO CLOSE SAID CONTACT GAP, PERMANENTLY MAGNETIZED MEANS HAVING ITS MAGNETIC AXIS DISPOSED SUBSTANTIALLY IN ALIGNMENT WITH SAID PATH OF RELUCTANCE TO PROVIDE A MAGNETIC FIELD DIRECTLY EMBRACING SAID SWITCHING MEANS AND EXTENDING IN A DIRECTION TO OP- 